Signal for telephone-switchboards.



No. 804,256. PATENTED NOV. 14, 190 5. F. R. MQBERTY.

SIGNAL PGR TELEPHONE SWITGHBOARDS.

APPLICATION FILED JULY 11.1902.

2 SHEETS-SHEET 1.

WITNESSES INVENTOR BMW ATTORNEY mnnsw a mum co, nnnnnnnnnnnnnnnnnnnnnnnnnnnnnn c.

PATENTED NOV. 14, 1905.

P. R. MOBERTY. SIGNAL FOR TELEPHONE SWITGHBOARDS.

APPLICATION FILED JULY 11.1902.

2 SHEETSSHBET 2.

I'FM I PH WITNESSES INVENTOR ATTORNEY UNITED STATES PATENT OFFICE.

I FRANK R. MGBERTY, OF EVANSTON, ILLINOIS, ASSIGNOR TO WESTERN ILLINOIS.

SIGNAL FOR TELEFHONE-SWITCHBOARDS.

Specification of Letters Patent.

Patented Nov. 14, 1905.

Application filed July 11, 1902. Serial No. 115,131.

To all whom, it may concern:

Be it known that I, FRANK R. MGBERTY, a citizen of the United States, residing at Evans ton, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Signals for Telephone- Switchboards, of which the following is afull, clear, concise, and exact description.

My invention concerns visible signals for telephone-switchboards and means for operating them automatically to call for connection and disconnection.

It consists in a new form of visible signal and circuits for a' telephone switchboard adapted for the operation of signals.

The invention is illustrated in the attached drawings, of which Figures 1, 2, 3, and 4 represent the new visible signal, while Fig. 5 is a diagram illustra tive of the circuits of the switchboard. Fig.

-1 is a side elevation of the signal, the trunnion-lugs being broken away better to display the moving parts. Fig. 2 is a plan thereof. Fig. 3 is a front elevation. Fig. 4 is a rear elevation. Fig. 5 is a diagram representing two subscribers telephone-lines centering in a switchboard in acentral oiiice, together with link conductors for connecting lines and superbe of the ordinary two-spool form, are carried on a common base-plate 0 of magnetic material, which may also form the support or mounting for the signal. The polar portions of these magnets pass through a support and trunnion-plate d. .On a spindle or 'pivot d, passing through lugs in "this plate, are mounted the two armatures a b'of the two magnets, respectively, and the pivoted indicator-lever e. The pivotal support of the armature a is beneath its center of gravity and between the said center and the poles of its magnet, so that the armature tends to fall away from the magnet. The pivot of the armature b is above its center of gravity and farther from the poles of its magnet, so that this armature also tends to fall away from the magnet. By reason of the pivoting of the armatures and indicator-lever upon the same axis there is no rubbing contact in the operation of the armatures to operate the lever, so that a frictionless engagement of said parts is obtained.

The indicator-arm e is nearly counterbalanced by a small weight at its rear extremity; but the indicator is of such weight that it tends to pass to its lower position. The armature a when resting back from the magnet a engages the rear extremity of the indicatorlever, adding its weight to that of the counterbalance, overbalancing the indicator and bringing it into its upper position. Thus when the magnet a is excited and attracts its armature the indicator-arm is relieved of the weight of its armature and the weight of the indicator brings it to its lower position. The armature b carries a short lever 6 engaging the indicator-lever 6 between its pivotal support and the indicator, so that the armature I) when attracted forces the indicator to its upper position. The indicator is covered when it lies in its upper position by a plate f, but when in its lower position lies before an opening f in the plate, where it is in view of the operator. The armature 6 is provided with an insulated contact o against which it bears when in its rear position. Thus when the magnet b is excited contact with its anvil is broken-at the same time that the indicator is restored to its concealed position.

Referring now to the diagram Fig. 5, the substations are furnished with the telephone sets of well-known form, preferably adapted for central-battery transmission and having telephone-switches for closing the circuits during the use of the telephones to control the central-oflice signals.

The line conductors 1 and 2 are led to the line-contacts of spring-jacks g in a multiple switchboard. A visible line signal of the construction described is provided for each line. The magnet a of this signal is constructed of high impedance and resistance and is connected in a permanent branch from the line conductor 1 to one pole of the central battery it. A branch to earth or to the other pole of the same battery is normally present, but is controlled at the contact of the armature Z), whereby it is normally closed, but is open when the magnet I) is excited. The line conductor 2, which is joined by this branch, is connected with the test-rings of the multiple spring-jacks. The magnet Z) of the signal is made of comparatively low resistancesay of onehundred ohms-and is interposed directly in the line conductor 1 betweenthe junction therewith of the magnet a andthe spring-jacks of the switchboard. This magnet should be shunted by a condenser or noninductive resistance to avoid the obstruction of voice-currents.

Pairs of plugs '11 and c" are furnished with the usual operators listening and ringing keys, telephone, and generator. Condensers 7c and la are interposed in theconductors 3 and 4, which constitute the plug-circuit. As-

plug-circuit between the plug i and the condenser therein to the grounded pole of the central battery It. The other magnet b of the same signal is connected in another branch 6 from a corresponding point of the conductor 3- of the plug-circuit to the free pole of the same battery. The supervisory signal Z, associated with plug 6, is similarly connected with the plug-circuit 3 L with respect to the plug i.

The circuits above described form no part of the present invention, but constitute the subject-matter of a divisional application filed January 20, 1905, Serial No.'241,962.

While this apparatus is idle the "indicators of all the signals are out of view, being overbalanced by the weight of the armatures a. When a user of the telephone at a substation takes the telephone from itsswitch and the circuit is closed at the substation, current from the battery it flows through the magnet a of the line-signal to the substation, return ing through the earth branch closed by the I of the earth,- the line conductor 2, with which they are connected, being-grounded through the switch-contacts o ofthe line-signals of armature b of the signal.

As before described, relieving the indica tor-arm e from the weight of the'armature a permits the indicator to come into view to in- 2i dicate the subscribers call.

swers the call by inserting the plug i into a Thereby circuitis' closed from battery 7 through the magnet a of the line-signal to line conductor 1, thence to conductor 4 of the plug-circuit, through It will be noted that spring-jack of the line.

the branch 5 to earth. this current traverses not only the magnet a of the line-signal, but the magnet b of the same signal and the magnet a of the supervisory signal associated with the plug a.

ment of the magnet b of the line-signal draws up the armature b and forces the indicator back to its concealed position, at the same time breaking the. ground branch from line conductor 2. The excitement of magnet a of the supervisory signal Zby drawing up the armature a, and thus relieving the indicator- The The operator anj The excitearm of thatsignal from its-weight,-:tends to display the indicator of the supervisory signa'l; but at the same moment battery hfinds circuit through the magnet hot the supervisory signal to the line conductor 2, thence to the substation, returning to the central ofiice and to earth through the magnet 11 of the linesignal and the magnet 64 of the supervisory signal. Thus both magnets a and b of the supervisory signal become active simultaneouslyin answering a call and the indicator that the indicator thereof remains concealed;

but as this circuit includes only the magnet a of the supervisory signal Ztheindicator-of this supervisory signal" is permitted to come into-view in condition to indicate-the response of the called party.

Taking the telephone from its switch-at the called station completes a circuit like that'before traced, in which current'is supplied for exciting the magnet b of the supervisory signal,-and the indicator of the signal l is thereby hidden.

It will be apparent that the movement of the telephone-switches will control the corre'- sponding supervisory signals, either signal being displayed when" the telephone atthe station to which it refersis placed'on thesw-itc'hhook. Neither of the line-signals isdisplayed after connection has been established.

iVhen the indicators of both supervisory signals-appear, their indication is taken as a call for disconnection, both telephones having been replaced on theirsw-itches.

It will be observed while the'apparat-us is in its idle=or inert condition-the test-rings of the multiple jacksare reduced to the potential their respective lines. 1 When I connection is made with any line by means of the plug,

however, the battery it becomes connected withthese test'rin-gs, while at the same time the earth-branch'f-rom the line conductor 2 is broken. Thereafter the test-ri-ngs-are electrified to aconsiderable potential above the earth, so-that they shall test busyat the other 2. The combination with a pivoted weighted indicator-arm, said arm being balanced to take a position to display the indicator when free. of an overbalancing weighted armature normally engaging said indicator-arm, to hold the indicator in its concealed position, a magnet adapted to attract said armature to permit the indicator to tilt into a position of display, and aseparate pivoted armature adapted to engage said indicator-arm to act thereon in the same direction as the overbalancing-armature, as described. I

8. In combination, in a visible signal, the weighted indicator-arm e, the overbalancingarmature a and the magnet therefor, the pivoted armature b and the lever 6 thereof adapted to engage the indicator-arm, and the magnet 7), as described.

4:. The combination with a pivoted indicator-lever carrying an indicator on its long arm,

said arm being balanced to take a position of display when free,the overbalancing-armature bearing upon its short arm when unattracted, and the magnet for moving said armature, a

pivoted armature adapted, when attracted, to

and lever being pivoted in the same axial line,

whereby a frictionless engagement is obtained.

In witness whereof I hereunto subscribe my name this 13th day of June, A. D. 1902.

FRANK R. MoBERlY. Witnesses:

EDWIN H. SMYTHE, FREDERICK A. WATKINS. 

